Because one-time use cameras are manufactured in very large quantities, small changes in costs of individual components present major consequences in aggregation. Biasing elements, such as small metal springs are relatively costly items in one-time use cameras, particularly if the cost of assembly is considered. Resilient elements can be provided as portions of larger molded plastic components, but this can present problems in achieving accurate spring biasing and in detecting defects.
U.S. Pat. No. 5,472,543 discloses a method for accurately attaching compliant labels to camera bodies. Compliant labels are cut from larger sheets of material. It is ordinarily easier to provide uniform physical characteristics in conventionally manufactured shape material than in molded plastic components.
It is known to provide labels and other one-time use camera parts that are replaced when the camera is recycled. U.S. Pat. No. 5,761,542 discloses a one-time use camera in which a film door includes an anti-backup pawl that breaks when the film door is opened and must be replaced to recycle the camera. The shortcoming is that the film door must include the anti-backup pawl.
It is known to load film in a one-time use camera by installing a film cartridge, light-tightly closing the camera, disabling an anti-backup, and prewinding the film onto a second spool by rotating an exposed portion of the second spool. (See, for example, U.S. Pat. No. 4,972,649 and Japanese Pat. Publication JP5-134361, published May 28, 1993) The anti-backup is reenabled after the film is prewound. The shortcoming is that the enabling and reenabling are additional steps and are not simple to perform using automated equipment.
JP7-114147 (published May 2, 1995) discloses an anti-bakup pawl that is biased by a projection of the back cover. The back cover is shown as closing the film chambers.
It would thus be desirable to provide a method for loading a one-time use camera in which an anti-backup system remains incomplete and nonfunctional until prewinding of a filmstrip is completed.